By "real", no one flies through the air nor lives through 5 minutes of fighting, being thrown, tossed, punched, kicked and hit with a crow bar only to rise up in the next scene.
This movie uses high level karate-ka as actors instead of actors playing the part. The karate-ka are better at their chosen craft than acting, but no matter - the story moves along nicely. So is the portrayed training. In that regard its a very realistic martial arts movie and the fighting is quite close to what it would be like. The strikes are deadly; people die and the fight is over with quickly.
The plot involves 3 karate students of which 2 are used to illustrate how power and skill can corrupt ones spirit. One student is corrupted, another tries to remain pure to his teachings and the lesser seen one tries keep every one honest. This plot unfolds in pre WWII Japan where the country itself is coming to terms with historic warrior culture amongst opportunists taking advantage of the poorer populace. If this sounds vague, its intentional.
The movie has English sub titles. The only place where it seems to get a little silly is the final fight scene. Not that its poorly done.... it seems to be a little out of context. Overall, the movie moves alonge nicely and it does not ask you to suspend reality.
The two main characters are shown doing their belt level kata during the credits at the end, and you can readily appreciate their skill.
This is off the main stream for most martial arts movies and may not appeal to most. I do think though that anyone that practices martial arts - regardless of style - will enjoy this movie. For others, as an "action movie", you may want to look elsewhere.